A systematic approach to weaning from extracorporeal membrane oxygenation in patients with refractory cardiac failure

Head-to-toe bedside ultrasound for adult patients on extracorporeal membrane oxygenation

Bedside ultrasound represents a well-suited diagnostic and monitoring tool for patients on extracorporeal membrane oxygenation (ECMO) who may be too unstable for transport to other hospital areas for diagnostic tests. The role of ultrasound, however, starts even before ECMO initiation. Every patient considered for ECMO should have a thorough ultrasonographic assessment of cardiac and valvular function, as well as vascular anatomy without delaying ECMO cannulation. The role of pre-ECMO ultrasound is to confirm the indication for ECMO, identify clinical situations for which ECMO is not indicated, rule out contraindications, and inform the choice of ECMO configuration. During ECMO cannulation, the use of vascular and cardiac ultrasound reduces the risk of complications and ensures adequate cannula positioning. Ultrasound remains key for monitoring during ECMO support and troubleshooting ECMO complications. For instance, ultrasound is helpful in the assessment of drainage insufficiency, hemodynamic instability, biventricular function, persistent hypoxemia, and recirculation on venovenous (VV) ECMO. Lung ultrasound can be used to monitor signs of recovery on VV ECMO. Brain ultrasound provides valuable diagnostic and prognostic information on ECMO. Echocardiography is essential in the assessment of readiness for liberation from venoarterial (VA) ECMO. Lastly, post decannulation ultrasound mainly aims at identifying post decannulation thrombosis and vascular complications. This review will cover the role of head-to-toe ultrasound for the management of adult ECMO patients from decision to initiate ECMO to the post decannulation phase.

Parameters associated with successful weaning of veno-arterial extracorporeal membrane oxygenation: a systematic review

PURPOSE

Veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) can be used to restore organ perfusion in patients with cardiogenic shock until native heart recovery occurs. It may be challenging, however, to determine when patients can be weaned successfully from ECMO-surviving without requiring further mechanical support or heart transplant. We aimed to systematically review the medical literature to determine the biomarkers, hemodynamic and echocardiographic parameters associated with successful weaning of VA-ECMO in adults with cardiogenic shock and to present an evidence-based weaning algorithm incorporating key findings.

METHOD

We systematically searched PubMed, Embase, ProQuest, Google Scholars, Web of Science and the Grey literature for pertinent original research reports. We excluded studies limited to extracorporeal cardiopulmonary resuscitation (ECPR) as the neurological prognosis may significantly alter the decision-making process surrounding the device removal in this patient population. Studies with a mixed population of VA-ECMO for cardiogenic shock or cardiac arrest were included. We excluded studies limited to patients in which ECMO was only used as a bridge to VAD or heart transplant, as such patients are, by definition, never "successfully weaned." We used the Risk of Bias Assessment tool for Non-Randomized Studies. The study was registered on the International prospective register of systematic reviews (PROSPERO CRD42020178641).

RESULTS

We screened 14,578 records and included 47 that met our pre-specified criteria. Signs of lower initial severity of shock and myocardial injury, early recovery of systemic perfusion, left and right ventricular recovery, hemodynamic and echocardiographic stability during flow reduction trial and/or pump-controlled retrograde trial off predicted successful weaning. The most widely used parameter was the left ventricular outflow tract velocity time integral, an indicator of stroke volume. Most studies had a moderate or high risk of bias. Heterogeneity in methods, timing, and conditions of measurements precluded any meta-analysis.

CONCLUSIONS

In adult patients on VA-ECMO for cardiogenic shock, multiple biomarkers, hemodynamic and echocardiographic parameters may be used to track resolution of systemic hypoperfusion and myocardial recovery in order to identify patients that can be successfully weaned.

Survival and neurological outcome after out-of-hospital cardiac arrest treated with and without mechanical circulatory support

Aim

The aim of this study was to describe the survival and neurological outcome in patients with OHCA treated with and without mechanical circulatory support (MCS).

Methods

This was a retrospective observational cohort study on patients with OHCA admitted to Aarhus University Hospital, Denmark, between January 2015 and December 2019. Kaplan-Meier estimates were used to evaluate 30-day and 30–180-day survival. Cox regression analysis was used to assess the association between covariates and one-year mortality.

Results

Among 1,015 patients admitted, 698 achieved return of spontaneous circulation (ROSC) before admission, 101 patients with refractory OHCA received mechanical circulatory support (MCS) and the remaining 216 patients with refractory OHCA did not receive MCS treatment. Survival to hospital discharge was 47% (478/1015). Good neurological outcome defined as Cerebral Performance Categories 1–2 were seen among 92% (438/478) of the patients discharged from hospital. Median low-flow was 15 [8–22] minutes in the ROSC group and 105 [94–123] minutes in the MCS group. Mortality rates were high within the first 30 days, however; 30–180-day survival in patients discharged remained constant over time in both patients with ROSC on admission and patients admitted with MCS. Advanced age > 70 years (hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.11–3.49), pulseless electrical activity (HR 2.39, 95% CI 1.25–4.60) and asystole HR 2.70, 95% CI 1.25–5.95) as initial rhythms were associated with one-year mortality in patients with ROSC.

Conclusions

Short-term survival rates were high among patients with ROSC and patients receiving MCS. Among patients who survived to day 30, landmark analyses showed comparable 180-day survival in the two groups despite long low-flow times in the MCS group. Advanced age and initial non-shockable rhythms were independent predictors of one-year mortality in patients with ROSC on admission.

Mechanical circulatory support for refractory out-of-hospital cardiac arrest: a Danish nationwide multicenter study

Background

Mechanical circulatory support (MCS) with either extracorporeal membrane oxygenation or Impella has shown potential as a salvage therapy for patients with refractory out-of-hospital cardiac arrest (OHCA). The objective of this study was to describe the gradual implementation, survival and adherence to the national consensus with respect to use of MCS for OHCA in Denmark, and to identify factors associated with outcome.

Methods

This retrospective, observational cohort study included patients receiving MCS for OHCA at all tertiary cardiac arrest centers (n = 4) in Denmark between July 2011 and December 2020. Logistic regression and Kaplan–Meier survival analysis were used to determine association with outcome. Outcome was presented as survival to hospital discharge with good neurological outcome, 30-day survival and predictors of 30-day mortality.

Results

A total of 259 patients were included in the study. Thirty-day survival was 26%. Sixty-five (25%) survived to hospital discharge and a good neurological outcome (Glasgow–Pittsburgh Cerebral Performance Categories 1–2) was observed in 94% of these patients. Strict adherence to the national consensus showed a 30-day survival rate of 30% compared with 22% in patients violating one or more criteria. Adding criteria to the national consensus such as signs of life during cardiopulmonary resuscitation (CPR), pre-hospital low-flow < 100 min, pH > 6.8 and lactate < 15 mmol/L increased the survival rate to 48%, but would exclude 58% of the survivors from the current cohort. Logistic regression identified asystole (RR 1.36, 95% CI 1.18–1.57), pulseless electrical activity (RR 1.20, 95% CI 1.03–1.41), initial pH < 6.8 (RR 1.28, 95% CI 1.12–1.46) and lactate levels > 15 mmol/L (RR 1.16, 95% CI 1.16–1.53) as factors associated with increased risk of 30-day mortality. Patients presenting signs of life during CPR had reduced risk of 30-day mortality (RR 0.63, 95% CI 0.52–0.76).

Conclusions

A high survival rate with a good neurological outcome was observed in this Danish population of patients treated with MCS for OHCA. Stringent patient selection for MCS may produce higher survival rates but potentially withholds life-saving treatment in a significant proportion of survivors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03606-5.